The present invention relates to a light controller in an image pickup device such as a still camera and a digital camera, or in a projector. In particular, the present invention relates to a light controller such as a shutter provided in an optical path of an optical device for shutting off shooting light or projection light.
A light controller is generally provided on a substrate having an optical path opening at the center of a shooting optical path or projection optical path of an optical device such as a camera and a projector. One or several blades are rotatably supported by pins on the substrate, and tips of the blades face the optical path opening so as to open or close an optical path, thereby controlling an amount of light. A light controlling blade such as a shutter blade is provided on the substrate to move reciprocally within a predetermined angle between a position where the blade covers the optical opening and a position away from the opening. The blade is connected to a driver such as a motor separately mounted on the substrate with a conductor.
Japanese Patent Publications (Kokai) No. 2001-228504, No. 2003-066506, and No. 2003-222927 have disclosed conventional devices having structures shown in FIGS. 8 to 11(a) and 11(b). As shown in FIG. 8, a pair of blades SH is rotatably supported on a substrate having an optical path opening at the center thereof, and the blades SH facing each other swing in opposite directions so as to open or close the optical path opening. Conventionally, tip edges of the blades abut against projecting stopper walls integrated with the substrate, so that the movement of the blades can be limited at the open and closed positions.
As shown in FIGS. 8 and 9, a stopper wall SP1 abuts against the tip of the blade SH to limit the same at the closed position, and a stopper wall SP2 limits the tip of the blade SH at the open position. Accordingly, it is necessary to provide the stopper walls such as projections on the substrate at the open and closed positions of the blades, thereby increasing a size of the substrate. Furthermore, a single driver moves the pair of blades in two directions through a conducting lever.
When the substrate has the stopper walls at the open and closed positions where the blades opens and closes the optical path opening, it is difficult to reduce a size of the substrate and make a structure of an apparatus simple. Especially, when three or more blades are provided on the substrate to quickly open and close the optical path opening, it is necessary to provide six or more stopper walls with high precision, thereby increasing a size and making an apparatus complex.
When the tip edges of the blades abut against the stopper walls, the blades may rebound or deform. If the blades rebound upon abutting against the stopper walls, the blades may slightly open the optical path, thereby leaking light. The blades may vibrate upon rebounding, thereby causing a large influence on a shooting condition. Further, as shown in FIGS. 11(a) and 11(b), when the blades abut against the stopper walls SP1 and SP2, the blades bend to create a gap at overlapped portion, thereby leaking light. When the blades bend, the blades tend to rebound more often.
As described above, in the conventional structures, the tips of the shutter blades abut against the stopper walls at the open and closed positions. Accordingly, it is difficult to prevent light from leaking when the blades bend or rebound, and to move the blades smoothly.
In view of the problems described above, an object of the present invention is to provide a light controller in which it is possible to provide a stopper unit on a substrate to stop a blade at open and closed positions for adjusting an amount of light, and to prevent the blade from rebounding.
Another object of the present invention is to provide a light controller in which it is possible to provide a plurality of blades for quickly opening and closing without increasing a size of a stopper unit for stopping the blades at open and closed positions, and without increasing a rebounding of the blades, thereby increasing a shutter speed of an optical device such as a camera apparatus.
Further objects and advantages of the invention will be apparent from the following description of the invention.